With AIDS, it had already become a major disaster for gays in the U.S. by the early 80s, but at that time we weren't considered relevant victims for "real" Americans.
I don't know exactly how a "threat" is defined. No disease is an existential threat, but whatever happens with ebola, HIV will infect orders of magnitude more than ebola. I think around one million Americans are HIV positive. So, it's at least strange to equate HIV to ebola.
